Apparatus for performing continuous treatment in vacuum

ABSTRACT

An apparatus for performing continuous treatment in vacuum including an inlet chamber, a first intermediate chamber, at least one vacuum treating chamber, a second intermediate chamber and a withdrawing chamber arranged in the indicated order in a direction in which base plates are successively transferred. An opening device normally closed and opened when a base plate is transferred therethrough is mounted on a wall at the inlet of the inlet chamber, between the adjacent chambers and on a wall at the outlet side of the withdrawing chamber. A conveyor device for conveying each base plate in a horizontal direction through the opening device is mounted in each of the chambers, and an evacuating device is also mounted in each chamber. A base plate storing device for storing a plurality of base plates in a magazine is mounted in the first and second intermediate chambers. At least one vacuum treating device is mounted in the vacuum treating chamber.

FIELD OF THE INVENTION

This invention relates to an apparatus for performing continuoustreatment in vacuum for carrying into practice a process for performingcontinuous treatment in vacuum which is used in connection with acontinuous sputtering apparatus for continuously depositing a thin filmon elements of semiconductor wafers, magnetic discs, communicationdevices, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a transverse sectional plan view of a sputtering apparatus ofthe prior art;

FIG. 2 is a perspective view of an assembly of a base plate and a jigfed to the apparatus shown in FIG. 1;

FIG. 3 is a transverse sectional view of the sputtering apparatusaccording to an embodiment of the invention;

FIG. 4 is a sectional view taken along the line IV--IV in FIG. 3;

FIG. 5 is a sectional view taken along the line V--V in FIG. 3;

FIG. 6 is a schematic view of the embodiment of the invention shown inFIG. 3;

FIG. 7 is a vertical sectional view of the sputtering apparatusaccording to another embodiment of the invention;

FIG. 8 is a transverse sectional plan view of the embodiment of theinvention shown in FIG. 7; and

FIG. 9 is a schematic view of the embodiment of the invention shown inFIG. 7.

DESCRIPTION OF THE PRIOR ART

A continuous sputtering apparatus of the prior art will be described byreferring to FIGS. 1 and 2. The apparatus uses a base plate supportedbeforehand by a conveyor jig means, such as a pallet. As shown in FIG.2, the conveyor jig means 1 comprises two members 1a and 1b in the formof a letter C in cross section disposed in spaced juxtaposed relationwhich are formed with grooves 2, 2 respectively for receiving a baseplate 3 fitted therein.

The sputtering apparatus of the prior art comprises, as shown in FIG. 1,rails 4 for transferring the conveyor jig means 1, (hereinafter referredto as a jig), such as a pallet, which has the base plate 3 fittedtherein as aforesaid, a sealed casing 7, an inserting section forinserting the jig 1 in an inlet chamber 15 of the sealed casing 7 byhydraulic cylinders 5 and 6 cooperating with each other, and awithdrawing section for withdrawing from a withdrawing chamber 21 of thesealed casing 7 the jig 1 having the base plate that has been treated.

The sealed casing 7 includes, arranged in the order of the steps fortreating the base plate supported in the jig 1, the inlet chamber 15, asputter-etching chamber 17, a heating chamber 18, a sputtering chamber19, a cooling chamber 20 and the withdrawing chamber 21 defined by aside wall 8, partition walls 9, 9', 10, 10', 11, 11', 12, 12', 13 and13' and a side wall 14. A reserve inlet chamber 16 is formed in a sidewall of the inlet chamber 15 close to the rails 4. The inlet chamber 15has mounted therein a hydraulic cylinder 23 having a sealing lid 24 forthe reserve inlet chamber 16 which has a pallet, not shown, for thejig 1. Located outside the inlet chamber 15 is a hydraulic cylinder 25having another sealing lid 26 for the reserve inlet chamber 16, theinlet chamber 15 having a hydraulic cylinder 28 at the side wall 8 forforcing the jig 1 horizontally from a predetermined position in theinlet chamber 15 toward transfer surfaces on rails 30. In the reserveinlet chamber 16, a pipe 27 is mounted, while in the inlet chamber 15,an exhaust pipe 29 is mounted. The rails 30 for transferring the jig arelayed inside the sealed casing 7 and extend from a position which isalmost in the inlet chamber 15 to a position which is almost in thewithdrawing chamber 21 after passing through the partition walls 9, 9'to 13, 13'. The sputter-etching chamber 17 has mounted therein anexhaust pipe 31 and a sputter-etching electrode 32, and the heatingchamber 18 has an exhaust pipe 33 and heaters 34 mounted therein. Thesputtering chamber 19 has an exhaust pipe 37 and a cooling pipe, notshown, arranged on the rails 30. A sputtering gas is introduced into thesputter-etching chamber 17 and the sputtering chamber 19. A reservewithdrawing chamber 22 is formed leftwardly of the withdrawing chamber21 as viewed leftwardly from the direction in which the jig 1 istransferred. The withdrawing chamber 21 has mounted therein an exhaustpipe 38 and a hydraulic cylinder 39 receiving the jig 1 from thetransfer surfaces on the rails 30 for transporting same to apredetermined position which is leftwardly as viewed from the directionof transfer on the rails 30. A hydraulic cylinder 40 for pressing thejig 1 in the predetermined position horizontally is mounted on a sidewall 14'. Mounted in the withdrawing chamber 21 is a hydraulic cylinder41 having a sealing lid 42 for the reserve withdrawing chamber 22 whichhas a pallet, not shown, for the jig 1 mounted forwardly thereof withrespect to the direction in which the base plate is transferred. Ahydraulic cylinder 43 having a sealing lid 44 for the withdrawingchamber 22 is mounted outside the withdrawing chamber 21, and thereserve withdrawing chamber 22 has a pipe 45 mounted therein. Ahydraulic cylinder 46 for forcing the jig 1 out of the sealed casing 7is mounted outside the reserve withdrawing chamber 22 which is thesection for withdrawing the jig 1 supporting the base plate that hasbeen treated. Vacuum pumps, not shown, are connected to the exhaustpipes 29, 31, 33, 35, 37 and 38, and the pipes 27 and 45 areinterchangeably connected to vacuum pumps, not shown, and theatmosphere. The chambers are evacuated to degrees different from oneanother and are in dynamic equilibrium condition which may varydepending on the conductance (the value indicating the ease with which agas flows) measured in gaps formed between the chambers and the jig 1successively transferred through the partition walls 9, 9' to 13, 13',the flow rate of a sputtering gas introduced into the sputter-etchingchamber 17 and the sputtering chamber 19, and the speed at which thefluid is exhausted through the exhaust pipe of each chamber. In theapparatus of the prior art of the aforesaid construction, the jig 1supporting the base plate is placed on the rails 4 outside the sealedcasing 7 and transferred in the direction of an arrow a.

Then the jig 1 is moved from position A to position B in the directionof an arrow b by the hydraulic cylinder 5 mounted in the insertingsection which is away from the forward end portions of the rails 4, andforced to move in the direction of an arrow c by the hydraulic cylinder6, so that it is transferred to position C in the reserve inlet chamber16 which is closed at the inlet chamber side by the sealing lid 24driven by the hydraulic cylinder 23 mounted in the inlet chamber 15before being placed on a pallet supported on the sealing lid 24.

At the time the jig 1 is inserted in position C, the hydraulic cylinder25 mounted outside the inlet chamber 15 is actuated, to seal the reserveinlet chamber 16 with the sealing lids 24 and 26 and contain the jig 1in the sealed chamber. At the same time, the reserve inlet chamber 16 isexhausted substantially to the same degree as the inlet chamber 15through the pipe 27.

When the sealed chamber is rendered vacuum, the pallet and the jig 1 aremoved in the direction of an arrow d to position E in the inlet chamber15, and the sealing lid 24 is moved in the direction of the arrow d toposition F.

At the time the jig 1 is moved to position E, the hydraulic cylinder 28mounted on the side wall 8 of the inlet chamber 15 is actuated to forcethe jig 1 in the direction of an arrow e and place same on the rails 30.The result of this is that the jig 1 placed on the rails 30 istransferred pitch by pitch in the direction of an arrow f. After the jig1 is forced on to the rails 30 from position E, the sealing lids 24 and26 are restored to their original positions indicated by solid lines.

In the sputter-etching chamber 17, a voltage is impressed between thesputter-etching electrode 32 and the base plate supported by the jig 1,to give an impact to the surface of the base plate with an ionizedsputtering gas, to effect sputter-etching of the surface of the baseplate to remove minuscule foreign matters adhering thereto.

Then in the heating chamber 18, the base plate is heated by heaters 34,to cause impure gases adsorbed on the surface of the base plate andabsorbed in the interior of the base plate to be released therefrom andto raise the temperature of the base plate to a level suitable forsputtering treatment.

Then in the sputtering chamber 19, an impact by means of an ionized gasof the different sign from that of the ionized gas used forsputter-etching is given to the base plate, to subject the base plate tosputtering treatment for causing a sputtering material of the sputteringelectrode 36 to adhere to the base plate.

Thereafter the base plate is cooled in the cooling chamber 20, and a jig1' supporting the base plate subjected to sputtering treatment asplanned is supplied to the withdrawing chamber 21.

In the withdrawing chamber 21, the jig 1' transferred to position G isfed by the hydraulic cylinder 39 in the direction of an arrow g to movesame to position H. Then the jig 1' is fed by the hydraulic cylinder 40from position H in the direction of an arrow h, to transfer same toposition I on the pallet provided to the sealing lid 42 attached to thehydraulic cylinder 41.

Then the hydraulic cylinder 41 is actuated to move the sealing lid 42with the pallet and jig 1' in the direction of an arrow i from positionJ, I shown in solid lines to position L, K shown in broken lines.

At this time, an outer opening of the reserve withdrawing chamber 22 isclosed by the sealing lid 44 attached to the hydraulic cylinder 43, sothat as the inner sealing lid 42 moves to position L, the reservewithdrawing chamber 22 is closed with the jig 1' being located in thesealed chamber. Air is introduced from the atmosphere into the sealedchamber through the pipe 45, to render the internal pressure of thereserve withdrawing chamber 22 atmospheric. Thereafter the sealing lid44 is moved by means of the hydraulic cylinder 43 from position M toposition N.

The hydraulic cylinder 46 in the withdrawing section is then actuated tomove in the direction of an arrow j the jig 1' in position K on thepallet to place same on the rails 4, to withdraw the jig 1' having thebase plate subjected to sputtering, thereby completing a series ofoperations.

The aforesaid series of operations are repeated, to subject one baseplate after another to sputtering.

Some disadvantages are associated with the apparatus of the aforesaidconstruction of the prior art. The arrangement whereby a base platesupported by a jig is subjected to sputtering inevitably brings into thesputtering chamber impure gases adhering to the jig in the atmosphere,thereby raising the impure gas partial pressure and adversely affectingthe quality of the film formed on the base plate. Moreover, since thethermal capacity of a jig is higher than that of a wafer, the timerequired for effecting heating and cooling is prolonged. The jig is oflarger dimensions than the wafer, so that the apparatus to a wholebecomes large as compared with an apparatus using no jig. The operationis performed on base plates continuously by treating one base plate as aunit, and consequently the reserve inlet chamber is evacuated each timeone base plate is introduced thereinto. Thus in many cases, the timerequired for evacuating the chamber becomes longer than the timerequired for the treatments given to the base plate. This placeslimitations on the cycle time of the apparatus, making it impossible toincrease production speed. The jigs are transferred from the inletchamber to the withdrawing chamber in a tact system of one pattern, sothat difficulties are experienced to thoroughly heat the base plateswhich usually require a prolonged holding of the base plates at hightemperature. Last but not least important is that the vacuum systembecomes complex because all the chambers are evacuated independently ofeach other.

SUMMARY OF THE INVENTION

This invention has been developed for the purpose of obviating theaforesaid disadvantages of the prior art. Accordingly the invention hasas its object the provision of an apparatus for performing continuoustreatment in vacuum capable of depositing a thin film of high quality ina stable manner on each base plate which is high in productivity andenables a compact overall size to be obtained in an apparatus of thetype described.

In one feature of the invention, the apparatus comprises, arranged inthe direction in which base plates are transferred, an inlet chamber forthe base plate, a first intermediate chamber therefor, at least onechamber for performing sputtering or other treatment in vacuum, a secondintermediate chamber and a withdrawing chamber. Opening means areprovided in a side wall on the inlet side of the inlet chamber, betweenthe chambers and in a side wall on the outlet side of the withdrawingchamber for providing openings only when a base plate passestherethrough. Each chamber has mounted therein conveyor means forconveying each base plate horizontally through the opening means betweenthe adjacent chambers, and vacuum means. The first and secondintermediate chambers have base plate containing means mounted therein,and the chamber for performing sputtering or their treatment has mountedtherein at least one sputtering means or other means for performingtreatment in vacuum. By virtue of this construction, it is possible todeposit thin films of high quality in a stable manner on the base platescontinuously with high productivity. More specifically, the conveyormeans conveys each base plate by itself without using a conveyor jigmeans, thereby enabling impure gases brought into the chamber forperforming treatment in vacuum from the atmosphere to be reduced inamount. The apparatus can accommodate changes in the size of base plateswithout any trouble, thereby avoiding a reduction in productivity.

In another feature of the invention, base plate raising means capable ofbringing each base plate to a substantially upright position in whichthe base plate is in face-to-face relation to the sputtering means ismounted in the chamber for performing sputtering which is formed as achamber for performing treatment in vacuum. By virtue of this feature,foreign matters that are deposited on the base plates can be reduced inamount and a thin film of uniform thickness can be deposited on eachbase plate.

In still another feature of the invention, the chamber for performingsputtering comprises a sputtering chamber, a sputter-etching chamber forforming a thin film of metal, such as aluminum, on a bipolar IC, etc.,by performing sputtering in unlike sign on a base plate to sputter-etchsame before sputtering is performed on the base plate in the sputteringchamber, and a cooling chamber for cooling the base plate on whichsputtering has been performed in the sputtering chamber. In the case ofan MOS IC, however, there is no need to perform sputter-etching.

In accordance with a further feature of the invention, each base plateis subjected by itself to baking treatment by means of a heater, toenable sputtering to be performed with aluminum or the like without therisk of incorporation of impurities. By virtue of this feature, thedisadvantage that variations would occur in the results of bakingtreatment to which the base plates are subjected when they are treatedin a batch can be eliminated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 3, 4 and 5 show one embodiment of the invention. In a sealedcasing 51, an inlet chamber 52, a first intermediate chamber 53, asputter-etching chamber 54, a sputtering chamber 55, a cooling chamber56, a second intermediate chamber 57 and a withdrawing chamber 58 arearranged successively in the direction of movement of a base plate 3 tobe treated. As viewed in plan view, these chambers are arranged in theform of a letter U in a lying position. A first outside storing means 50is located outside the sealed casing 51 on the side of the inlet chamber52, while a second outside storing means 59 is located outside thesealed casing 51 on the side of the withdrawing chamber 58.

The first outside storing means 50 comprises a pair of conveyor belts 60and 61, and a cassette elevator 62 having a base plate cassette 63. Thecassette elevator 62 is connected to a drive source, not shown, whichmay comprise a motor and a ball screw in combination. The cassette 63 isconstructed such that it can contain base plates 3 on shelves arrangedin vertically spaced relation. In the first outside storing means 50 ofthe aforesaid construction, the base plates to be treated are directlyplaced on the conveyor belts 60 and 61 by themselves and not supportedby jigs, and the base plates 3 are conveyed to the position in which thecassette elevator 62 is located, to be placed on the shelves of thecassette 63. Each time one base plate 3 is placed on one of the shelvesin the base plate cassette 63, the cassette elevator 62 isintermittently moved upwardly a distance corresponding to one pitch ofthe shelves to place a predetermined number of base plates 3 in thecassette 63. After the predetermined number of base plates 3 are placedon the shelves of the cassette 63, the cassette elevator 62 operates incooperation with the conveyor belts 60 and 61, to feed one base plate 3after another from the cassette 63 to the inlet chamber 52.

A gate valve 64 is mounted between the first outside storing means 50and the inlet chamber 52 or on an inlet side wall of the inlet chamber52 and comprises a hydraulic cylinder, not shown, which is adapted toopen when the base plate 3 is introduced into the inlet chamber 52 bythe conveyor belts 60 and 61.

The inlet chamber 52 has mounted therein a pair of conveyor belts 65 and66, a cassette elevator 67 having a cassette 68, an exhaust port 69communicating with a vacuum pump 70 as shown in FIG. 5, a heater and anatmosphere leak means. The heater and the atmosphere leak means are notshown. The cassette elevator 67 and the base plate cassette 68 are ofthe same construction as the cassette elevator 62 and the base platecassette 63 respectively of the first outside storing means 50. One baseplate 3 after another is fed to the inlet chamber from the conveyorbelts 60 and 61 of the first outside storing means 50 by the pair ofbelt conveyors 65 and 66 through the gate valve 64, and placed on eachshelf of the base plate cassette 68 by means of the cassette elevator67. After a predetermined number of base plates 3 are placed in thecassette 68, the gate valve 64 is closed, and the inlet chamber 52 isevacuated through the exhaust port 69 to introduce thereinto a vacuum ofabout 10⁻⁵ Torr. Then baking of the base plate 3 is effected byactuating the heater to degass the base plates 3, and thereafter onebase plate 3 after another is fed from the base plate cassette 68 to thefirst intermediate chamber 53 by the cassette elevator 67 in cooperationwith the conveyor belts 65 and 66. The baking can thus be advantageouslyeffected in the sputter-etching chamber 54 or a newly installed chamber,not shown, between the first intermediate chamber 53 and thesputter-etching chamber 54, for example, with regard to one base plate 3after another, rather than in the inlet chamber 52 with regard to alarge number of base plates 3 in a batch, to permit the baking to beeffected uniformly without any variation.

A gate valve 71 is mounted between the inlet chamber 52 and the firstintermediate chamber 53 and has the same construction as the gate valve64 referred to hereinabove.

In the first intermediate chamber 53, a pair of conveyor belts 72 and73, a cassette elevator 74 having a base plate cassette 75, an exhaustport 76 communicating with a vacuum pump and a gas inlet means. Thevacuum pump and the gas inlet means are not shown. The cassette elevator74 and the base plate cassette 75 are of the same construction as thecassette elevator 62 and the base plate cassette 63 respectively of thefirst outside storing means 50. By adjusting the flow rate of gas, suchas N₂ gas introduced through the gas inlet means, that does not affectthe sputtering, and the velocity at which evacuation is effected by thevacuum pump connected to the exhaust port 76, the internal pressure ofthe intermediate chamber 53 can be rendered substantially equal to thatof the inlet chamber 52 or about 10⁻⁵ Torr, for example. Then the gatevalve 71 is opened and one base plate 3 after another is received fromthe conveyor belts 65 and 66 of the inlet chamber 52 through the gatevalve 71 and placed on the shelves of the cassette 75 through the actionof the cassette elevator 74. After a predetermined number of base plates3 are placed, the gate valve 71 is closed and the internal pressure ofthe first intermediate chamber 53 is rendered substantially equal to thepressure in the sputter-etching chamber 54 or about 10⁻³ Torr, forexample, by adjusting the flow rate of the gas introduced through thegas inlet means and the velocity at which evacuation is effected by thevacuum pump communicating with the exhaust port 76. Then by the cassetteelevator 74 cooperating with the conveyor belts 72 and 74, one baseplate 3 after another can be fed from the base plate cassette 75 to thesputtering chamber 54.

When the gate valve 71 between the inlet chamber 52 and the firstintermediate chamber 53 is opened, the internal pressure of the firstintermediate chamber 53 may be rendered higher than the internalpressure of the inlet chamber 52, to avoid introduction of H₂ O, O₂ andother gases that might adversely affect the sputtering or dust into thefirst intermediate chamber 53 from the inlet chamber 52. Also, theinternal pressure of the first intermediate chamber 53 may be renderedabout 10⁻⁶ Torr which is slightly lower than the internal pressure ofthe inlet chamber 52 which is 10⁻⁵ Torr, and the gate valve 77 may beopened even if there is introduction of gases or dust to a certaindegree, so as to exhaust the gases and dust by the pressure of 10⁻⁶ Torrbefore the base plates 3 are fed to the sputter-etching chamber 53.

The gate valve 77 is mounted between the first intermediate chamber 53and the sputter-etching chamber 54 and has the same construction as thegate valve 64.

In the sputter-etching chamber 54, a pair of conveyor belts 78 and 79,another pair of conveyor belts 80 and 81, an elevator 82, asputter-etching electrode 83, an exhaust port 84 communicating with avacuum pump, an inlet means for argon gas, for example, and a heater 85are mounted. The vacuum pump and the gas inlet means are not shown. Asshown in FIG. 4, the conveyor belts 78, 79, 80 and 81 are arranged inthe same horizontal plane close to one another and can pivotally movefrom a horizontal position in a vertical direction with the outer endside thereof serving as a pivot. As shown in FIG. 4, the elevator 82first causes the base plate 3 conveyed by the conveyor belts 78, 79, 80and 81 to the central portion of the sputter-etching chamber 54 to aposition P which is higher than the conveyor surfaces of the conveyorbelts 78, 79, 80 and 81, and then causes the base plate 3 to descend toa position Q on a sputter-etching electrode 83 after the conveyor belts78, 79, 80 and 81 have pivotally moved in the vertical direction. Thesputter-etching electrode 83 is located in a lower portion of thesputter-etching chamber 54 and the heater 85 is located in an upperportion thereof. The sputter-etching chamber 54 is maintained in dynamicequilibrium at a constant pressure, such as 10⁻³ Torr, which may varydepending on the flow rate of a sputtering gas introduced through themeans for introducing gas, such as argon gas, and the speed at whichevacuation is effected by the vacuum pump communicating with the exhaustport 84. From the conveyer belts 72 and 73 of thefirst intermediatechamber 53, one base plate 3 is fed by the conveyor belts 78 and 79through the gate valve 77 to the sputter-etching chamber 54 and conveyedby the conveyor belts 78, 79, 80 and 81 to the central portion of thesputter-etching chamber 54. Then the gate valve 77 is closed and thebase plate 3 is caused to ascend by the elevator 82. Then the conveyorbelts 78, 79, 80 and 81 are pivotally moved in the vertical direction,and the base plate 3 is caused to descend to position Q on thesputter-etching electrode 83 by means of the elevator 82. By impressinga voltage on the sputter-etching electrode 83, the base plate 3 can besubjected to sputter-etching. The base plate 3 thus treated is caused toascend by the elevator 82 to position P in which it is close to theheater 85 which heats the base plate 3 to a temperature suitable foreffecting sputtering. Meanwhile the conveyor belts 78, 79, 80 and 81 arereturned to the horizontal position, and the elevator 82 is moveddownwardly to deliver the heated base plate 3 to the conveyor belts 78,79, 80 and 81, before being delivered to the sputtering chamber 55.

A gate valve 86 is mounted between the sputter-etching chamber 55 andthe sputtering chamber 55 and has the same construction as the gatevalve 64.

In the sputtering chamber 55, a first pair of conveyor belts 87 and 88,a first rise arm 89, a first sputtering electrode 90, a shield 91 forkeeping sputtered particles from adhering to walls of the sputteringchamber 55, a first shutter 92, a second pair of conveyor belts 93 and94, a second rise arm 95, a second sputtering electrode 96, a secondshutter 97, a conveyor arm 99 movable between the first and second pairsof conveyor belts 87, 88 and 93, 94 along a ball screw 98, an exhaustport 100 communicating with a vacuum pump and a gas inlet means aremounted. The vacuum pump and the gas inlet means are not shown. Thesputtering chamber 55 is in dynamic equilibrium at a constant pressure,such as 10⁻³ Torr, which may vary depending on the flow rate ofsputtering gas, such as argon gas, introduced through the gas inletmeans and the speed at which the chamber 55 is evacuated by the vacuumpump communicating with the exhaust port 100. The first and secondconveyor belts 87, 88 and 93, 94 receive one base plate 3 after anotherfrom the conveyor belts 78, 79 and 80, 81 of the sputter-etching chamber54 and convey same in the same direction to a position R close to thefirst rise arm 89. The first rise arm 89 receives in horizontalcondition the base plate 3 conveyed to position R and, as shown in FIG.4, pivotally moves through substantially 90° from a position S in avertical direction, to bring the base plate 3 to an upright position inwhich it is juxtaposed against the first sputtering electrode 90. Afterthe base plate 3 is subjected to sputtering, the rise arm 89 is restoredto its position which is lower than the conveying surfaces of the firstpair of conveyor belts 87 and 88. After the base plate 3 is brought toan upright position as aforesaid, the first shutter 92 is opened and thefirst sputtering electrode 90 performs a first sputtering treatment onthe base plate 3, before the first shutter 92 is closed. The conveyorarm 99, which is connected to a drive source comprising the ball screw98 trained over the first and second pairs of conveyor belts 87, 88 and93, 94 and a motor, not shown, moves to a position T above the conveyorsurfaces of the first pair of conveyor belts 87 and 88 while the baseplate 3 is being subjected to the first sputtering treatment. Inposition T, the conveyor arm 99 receives from the first rise arm 89 thebase plate 3 that has been subjected to the first sputtering treatment,and moves to a position U above the conveyor surfaces of the second pairof conveyor belts 93 and 94 where it transfers the base plate 3 to thesecond rise arm 95, before returning toward the first pair of conveyorbelts 87 and 88. In position U, the second rise arm 95 receives the baseplate 3 from the conveyor arm 99 and pivotally moves throughsubstantially 90° to bring the base plate 3 to an upright position inwhich it is juxtaposed against the second sputtering electrode 96. Afterthe base plate 3 is subjected to sputtering treatment, the second risearm 95 pivotally moves back to the horizontal condition in which it islower than the conveyor surfaces of the second pair of conveyor belts 93and 94. After the base plate 3 is brought to the upright position asaforesaid, the second shutter 97 is opened to subject the base plate 3to the second sputtering treatment by means of the second sputteringelectrode 96, before the second shutter 97 is closed. The second pair ofconveyor belts 93 and 94 receive the base plate 3 that has beensubjected to the second sputtering treatment from the second rise arm 95and conveys same toward the cooling chamber 56. The sputtering chamber55 receives one base plate 3 from the conveyor belts 78, 79 and 80, 81of the sputter-etching chamber 54 through the gate valve 86 which isplaced on the first pair of conveyor belts 87 and 88. After the baseplate 3 is delivered to the sputtering chamber 55, the gate valve 86 isclosed, and the first pair of conveyor belts 87 and 88 convey the baseplate 3 to position R, when the first rise arm 89 pivotally movesthrough substantially 90° to bring the base plate 3 to an uprightposition. When the base plate 3 is brought to the upright position, thefirst shutter 92 is opened to subject the base plate 3 to a firstsputtering treatment. When the sputtering of the base plate 3 isfinished, the first shutter 92 is closed and the first rise arm 89 movespivotally toward a horizontal position to place the base plate 3 thathas been subjected to the first sputtering treatment on the conveyor arm99 standing by in position T, from which the conveyor arm 99 moves to aposition U above the second pair of conveyor belts 93 and 94, while thesecond rise arm 95 standing by below position U pivotally moves to bringthe base plate 3 to an upright position. At this time, the secondshutter 97 is opened and the second sputtering electrode 96 performs asecond sputtering treatment on the base plate 3 while the conveyor arm99 moves from position U toward the first pair of conveyor belts 87 and88. The second shutter 97 is closed and the second rise arm 95 pivotallymoves in a horizontal direction, to transfer the base plate 3 that hasbeen subjected to the second sputtering treatment to the second pair ofconveyor belts 93 and 94, to convey same to the cooling chamber 56.

A gate valve 101 is mounted between the sputtering chamber 55 and thecooling chamber 56 and has the same construction as the gate valve 64referred to hereinabove.

The cooling chamber 56 which is adjacent to and partitioned off thesputter-etching chamber 54 by a partition wall 102 has mounted therein apair of conveyor belts 103 and 104, an exhaust port 105 communicatingwith a vacuum pump and a gas inlet means. The vacuum pump and the gasinlet means are not shown. The exhaust port 105 is constructed such thatit cooperates with the exhaust port 84 of the sputter-etching chamber 54to define a circle, and the cooling chamber 56 shares the vacuum pumpwith the sputter-etching chamber 54 so as to be kept at the samepressure as the sputter-etching chamber 54. In the cooling chamber, thebase plate 3 is supplied from the sputtering chamber 55 via the gatevalve 101 and placed on the conveyor belts 103 and 104 in which the baseplate 3 is subjected to radiation cooling, before a base plate 3' now acompleted article is delivered to the second intermediate chamber 57.

A gate valve 106 of the same construction as the gate valve 64 ismounted between the cooling chamber 56 and the second intermediatechamber 57.

The second intermediate chamber 57 which is adjacent to and partitionedoff the first intermediate chamber 53 by a partition wall 107 hasmounted therein a pair of conveyor belts 108 and 109, a cassetteelevator 110 having a base plate cassette 111, an exhaust port 112 and agas inlet means. The gas inlet means is not shown. The cassette elevator110 and the base plate cassette 111 are of the same construction as thecassette elevator 62 and the base plate cassette 63 respectively of thefirst outside storing means 50. The exhaust port 112 is constructed suchthat it cooperates with the exhaust port 76 of the first intermediatechamber 53 to define a circle and communicates with the same vacuum pumpas the exhaust port 76. The vacuum pump is not shown. The secondintermediate chamber 57 receives the base plate 3' which is a completedarticle one by one from the conveyor belts 103 and 104 of the coolingchamber 56 through the gate valve 106, and the base plate 3' is placedin the base plate cassette 111 by means of the cassette elevator 110.When a predetermined number of base plates 3' are placed in the baseplate cassette 111, the gate valve 106 is closed and the pressure in thesecond intermediate chamber 57 is rendered substantially equal to thepressure prevailing in the withdrawing chamber 58 by adjusting the flowrate of the gas introduced by the means for introducing gas, such asnitrogen gas, and the velocity at which the chamber 57 is evacuated bythe vacuum pump through the exhaust port 112. Then one base plate 3'after another is fed from the base plate cassette 111 to the withdrawingchamber 58 by the conveyor belts 108 and 109 cooperating with thecassette elevator 110.

A gate valve 113 of the same construction as the gate valve 64 ismounted between the second intermediate chamber 57 and the withdrawingchamber 58.

The withdrawing chamber 58 is adjacent to and partitioned off the inletchamber 52 by a partition wall 114, and has mounted therein a pair ofconveyor belts 115 and 116, a cassette elevator 117 having a base platecassette 118, an exhaust port 110 and means for leaking air to theatmosphere. The air leaking means is not shown. The cassette elevator117 and the base plate cassette 118 are of the same construction as thecassette elevator 62 and the base plate cassette 63 respectively of thefirst outside storing means 50. The exhaust port 119 is constructed suchthat it cooperates with the exhaust port 69 of the inlet chamber 52 todefine a circle and communicates with the same vacuum pump 70 as theexhaust port 69. In the withdrawing chamber 58, one base plate 3' afteranother is received from the conveyor belts 108 and 109 of the secondintermediate chamber 57 through the gate valve 113 and placed on theconveyor belts 115 and 116, and the base plates 3' are placed in thebase plate cassette 118 through the operation of the cassette elevator117. After a predetermined number of base plates 3' are placed in thebase plate cassette 118, the gate valve 113 is closed and the exhaustport 119 is closed by means of a valve, not shown, and air is introducedinto the chamber 58 through the air leaking means, to render thepressure in the chamber 58 atmospheric. Then one base plate 3' afteranother is delivered from the base plate cassette 118 by the conveyorbelts 115 and 116 cooperating with the cassette elevator 117.

A gate valve 120 of the same construction as the gate valve 64 ismounted between the withdrawing chamber 58 and the second outsidestoring means 59 or on a side wall on the outlet side of the withdrawingchamber 58.

A portion of each of the chambers 52-58 at which the moving member isintroduced from the atmospheric side to the chamber side is providedwith an airtight seal in the form of a vacuum bellows or an O-ring.

The second outside storing means 59 comprises a pair of conveyor belts121 and 122, and a cassette elevator 123 having a base plate cassette124. The cassette elevator 123 and the base plate cassette 124 are ofthe same construction as the cassette elevator 62 and the base platecassette 63 respectively of the first outside storing means 50. Thesecond outside storing means 59 receives one base plate 3' after anotherfrom the conveyor belts 115 and 116 of the withdrawing chamber 58through the gate valve 120, and the conveyor belts 121 and 122 conveysame to a predetermined position for the cassette elevator 123 where thebase plate 3' is placed by the cassette elevator 123 in the base platecassette 124. After a predetermined number of base plates 3' aretemporarily placed in the base plate cassette 124, the gate valve 120 isclosed.

The sputtering apparatus of the aforesaid construction operates asfollows. The base plate 3 to be treated is freely placed on the conveyorbelts 60 and 61 of the first outside storing means 50 and conveyed to aposition in which the cassette elevator 62 is located, so that one baseplate 3 after another is placed in the base plate cassette 63 on one ofthe shelves therein. Each time one base plate 3 is placed on one shelf,the cassette elevator 62 moves upwardly a distance corresponding to thepitch of the shelves, to enable the base plate 3 conveyed theretothereafter to be accommodated. This operation is repeatedly carried out,so as to temporarily store in the base plate cassette 63 a predeterminednumber of base plates 3 that are conveyed to the means 50 at irregularintervals in time. When the number of base plates 3 stored in the baseplate cassette 63 reaches the predetermined number, the gate valve 64 onthe inlet side of the inlet chamber 52 is opened, and the cassetteelevator 62 of the first outside storing means 50 moves downwardly adistance corresponding to one pitch of the shelves to deliver one baseplate 3 after another to the inlet chamber 52 by the conveyor belts 60and 61 of the first outside storing means 50 and the belt conveyors 65and 66 of the inlet chamber 52.

The base plates 3 delivered continuously to the inlet chamber 52 areplaced one after another in the base plate cassette 68 by the cassetteelevator 67, and the gate valve 64 is closed when the base plates 3 inthe base plate cassette 63 of the first outside storing means 50 are allplaced in the base plate cassette 68 in the inlet chamber 52. Then theinlet chamber 52 is evacuated by the vacuum pump 70 through the exhaustport 69. At this time, the withdrawing chamber 58 is also evacuated.While the inlet chamber 52 is being evacuated, the base plates 3 aresubjected to baking by means of the heater to degass them, therebycompleting the operation of introducing the base plates 3 into thesputtering apparatus.

By adjusting the flow rate of the gas introduced into the chamber 52through the gas inlet means and the rate at which the chamber 52 isevacuated through the exhaust port 76 by the vacuum pump, the pressurein the first intermediate chamber 53 is rendered substantially equal tothat of the inlet chamber 52. Then the gate valve 71 between the inletchamber 52 and the first intermediate chamber 53 is opened, and thecassette elevator 74 in the inlet chamber 52 is moved downwardly adistance corresponding to one pitch of the shelves of the cassette 75,to convey one base plate 3 after another by the conveyor belts 65 and 66of the inlet chamber 52 and the conveyor belts 72 and 73 of the firstintermediate chamber 53 to the first intermediate chamber 53. In thefirst intermediate chamber 53, one base plate 3 after another is placedby the cassette elevator 74 in the base plate cassette 75, and the gatevalve 71 is closed when all the base plates 3 in the base plate cassette68 of the inlet chamber 52 are placed in the base plate cassette 75 ofthe first intermediate chamber 53. After the gate valve 71 is closed, anoperation for introducing the base plates 3 into the inlet chamber 52 isinitiated again.

The flow rate of the gas, such as N₂ gas, introduced through the gasinlet means into the first intermediate chamber 53 and the speed atwhich the chamber 53 is evacuated by the vacuum pump communicated withthe exhaust port 76 are adjusted, to render the pressure in the firstintermediate chamber 53 substantially equal to that in thesputter-etching chamber 54. Following this adjustment of the pressure,the gate valve 77 between the first intermediate chamber 53 and thesputter-etching chamber 54 is opened and the cassette elevator 74 in thefirst intermediate chamber 53 is moved downwardly a distancecorresponding to one pitch of the shelves, to deliver one base plate 3after another to the central portion of the sputter-etching chamber 54by the conveyor belts 72 and 73 in the first intermediate chamber 53 andthe conveyor belts 78, 79, 80 and 81 in the sputter-etching chamber 54.The gate valve 77 is closed each time one base plate 3 is conveyed.

Upon the base plate 3 being conveyed to the central portion of thesputter-etching chamber 54, the elevator 82 is actuated to raise thebase plate 3 temporarily to a position higher than the conveyor surfacesof the conveyor belts 78, 79, 80 and 81. Then the conveyor belts 78, 79,80 and 81 are pivotally moved in the vertical direction, and theelevator 82 is moved downwardly to move the base plate 3 to position Qabove the sputter-etching electrode 83. Thereafter a voltage isimpressed on the sputter-etching electrode 83 to subject the base plate3 to sputter-etching treatment for removing from the base plate 3foreign matters, such as an oxide film, that might be deposited thereon(this operation is necessary when aluminum sputtering is performed on abipolar IC). Following this sputter-etching operation, elevator 82 movesupwardly again to position P in which the base plate 3 is close to theheater 85, and the heater 85 is actuated to heat the base plate 3 to atemperature suitable for sputtering. Meanwhile the conveyor belts 78,79, 80 and 81 are pivotally moved in a horizontal direction. Followingheating of the base plate 3 by the heater 85, the elevator 82 movesdownwardly again to place the base plate 3 on the conveyor belts 78, 79,80 and 81. At this time, the gate valve 86 between the sputter-etchingchamber 54 and the sputtering chamber 55 is opened, and the base plate 3is conveyed by the conveyor belts 78, 79, 80 and 81 of thesputter-etching chamber 54 and the first pair of conveyor belts 87 and88 of the sputtering chamber 55 to position R in the sputtering chamber55, before the gate valve 86 is closed. Then the gate valve 77 betweenthe first intermediate chamber 53 and the sputter-etching chamber 54 isopened, to be ready for introduction of the next following base plate 3into the sputter-etching chamber 54.

At the time the base plate 3 is conveyed to position R in the sputteringchamber 55, the first rise arm 89 is pivotally moved from a horizontalposition S in a vertical direction to bring the base plate 3 to anupright position in which it is juxtaposed against the first sputteringelectrode 90. A voltage is impressed on the first sputtering electrode90 to cause ionized argon gas to impinge on the sputtering electrode 90to release the atomic particles of the film forming material. The firstshutter 92 is opened and the base plate 3 is subjected to the firstsputtering treatment. The first shutter 92 is closed when the firstsputtering treatment is finished. Then the first rise arm 89 pivotallymoves from the vertical position to the horizontal position to place thebase plate 3 on the conveyor arm 99 in position T on the first pair ofconveyor belts 87 and 88, and the conveyor arm 99 moves to a position Uabove the second pair of conveyor belts 93 and 94. Upon the base plate 3being moved to position U, the second rise arm 95 pivotally moves from ahorizontal position to a vertical position to bring the base plate 3 toan upright position in which it is juxtaposed against the secondsputtering electrode 96. A voltage is impressed on the second sputteringelectrode 96 to cause ionized argon gas to impinge on the sputteringelectrode 96 to release the atomic particles of the film formingmaterial. The second shutter 95 is opened and the base plate 3 issubjected to a second sputtering treatment and the second shutter 95 isclosed when the second sputtering treatment is finished. The reason whytwo sputtering treatments are given is because it is necessary tocontinue operation without increasing the tact time even when the filmto be formed needs to have a large thickness. During the secondsputtering treatment, the conveyor arm 99 is moved to a position inwhich it is away from the second pair of conveyor belts 93 and 94. Uponcompletion of the second sputtering treatment, the second rise arm 95moves pivotally in a horizontal direction to place the base plate 3 onthe second pair of conveyor belts 93 and 94. Then the gate valve 101between the sputtering chamber 55 and the cooling chamber 56 is opened,and the base plate 3 is conveyed by the second pair of conveyor belts 93and 94 of the sputtering chamber 55 and the pair of conveyor belts 103and 104 of the cooling chamber 56 to the cooling chamber 56. Thereafterthe gate valve 101 between the sputtering chamber 55 and the coolingchamber 56 is closed, and the gate valve 86 between the sputteringchamber 55 and the sputter-etching chamber 54 is opened.

The base plate 3 conveyed to the cooling chamber 56 is subjected toradiation cooling on the belt conveyors 103 and 104. After the baseplate 3 is cooled, the gate valve 106 between the cooling chamber 56 andthe second intermediate chamber 57 is opened, so that a base plate 3'which is a completed article is conveyed by the pair of conveyor belts103 and 104 of the cooling chamber 56 and the pair of conveyor belts 108and 109 in the second intermediate chamber 57 to the second intermediatechamber 57.

The base plates 3 are treated one by one in the sputter-etching chamber54, sputtering chamber 55 and cooling chamber 56.

The base plate 3' conveyed to the second intermediate chamber 57 isconveyed by the conveyor belts 108 and 109 to the position in which thecassette elevator 110 is located, and the cassette elevator 110 is movedupwardly for a distance corresponding one pitch of the shelves to placeeach base plate 3 on one of the shelves of the base plate cassette 111,so that base plates 3 are housed in the base plate cassette 111. When apredetermined number of base plates 3' are housed in the base platecassette 111, the gate valve 106 between the cooling chamber 56 and thesecond intermediate chamber 57 is closed, and the flow rate of the gasintroduced through the gas inlet means and the speed at which thechamber 57 is evacuated through the exhaust port 112 communicating withthe vacuum pump are adjusted, to render the pressure in the secondintermediate chamber 57 substantially equal to that in the withdrawingchamber 58. After the pressure is adjusted, the gate valve 113 betweenthe second intermediate chamber 57 and the withdrawing chamber 58 isopened.

After the gate valve 113 is opened, the cassette elevator 110 in thesecond intermediate chamber 57 is moved downwardly a distancecorresponding to one pitch of the shelves, to deliver one base plate 3'after another from the base plate cassette 111. The base plate 3' isconveyed by the conveyor belts 108 and 109 in the second intermediatechamber 57 and the conveyor belts 115 and 116 in the withdrawing chamber58 to the position in which the cassette elevator 117 in the withdrawingchamber 58 is located, and the cassette elevator 110 is moved upwardly adistance corresponding one pitch of the shelves to place each base plate3' on one of the shelves in the base plate cassette 111. When all thebase plates 3' are placed in the base plate cassette 118 in thewithdrawing chamber 58, the gate valve 113 between the secondintermediate chamber 57 and the withdrawing chamber 58 is closed, andthe exhaust port 119 is closed by a valve, not shown, to allow air to beintroduced from the atmosphere through the leak means, to render thepressure in the withdrawing chamber 58 atmospheric, before the gatevalve 120 between the withdrawing chamber 58 and the second outsidestoring means 59 is opened.

After the gate valve 113 is opened, the cassette elevator 110 in thesecond intermediate chamber 57 moves downwardly a distance correspondingto one pitch of the shelves to deliver one base plate 3' after anotherfrom the base plate cassette 111. The base plate 3' is conveyed by theconveyor belts 108 and 109 in the second intermediate chamber 57 and theconveyor belts 115 and 116 in the withdrawing chamber 58 to the positionin which the cassette elevator 117 is located in the withdrawing chamber58, and the cassette elevator 117 moves upwardly a distancecorresponding to one pitch of the shelves to place each base plate 3' onone of the shelves in the base plate cassette 118. When all the baseplates 3' in the base plate cassette 111 in the second intermediatechamber 57 are placed in the base plate cassette 118 in the withdrawingchamber 58, the gate valve 113 between the second intermediate chamber57 and the withdrawing chamber 58 is closed and the exhaust port 119 isclosed by a valve, not shown, so that air is introduced into thewithdrawing chamber 58 from the atmosphere through the air leak means torender the pressure in the withdrawing chamber 58 atmospheric before thegate valve 120 between the withdrawing chamber 58 and the second outsidestoring means 59 is opened.

One base plate 3' after another is withdrawn from the base platecassette 118 by the conveyor belts 115 and 116 in the withdrawingchamber 58 cooperating with the cassette elevator 117, and transferredto the conveyor belts 121 and 122 of the second outside storing means59. The base plate 3' is conveyed to the position in which the cassetteelevator 123 is located, and the cassette elevator 123 moves a distancecorresponding one pitch of the shelves to store the base plate 3'temporarily in the base plate cassette 124. When all the base plates 3'in the base plate cassette 118 in the withdrawing chamber 58 are placedin the base plate cassette 124 of the second outside storing means 59,the gate valve 120 is closed.

When necessary, the second outside storing means 59 may be actuated tomove the cassette elevator 123 thereof downwardly a distancecorresponding to one pitch of the shelves, to withdraw one base plate 3'after another from the base plate cassette 124 before the base plates 3'are delivered to the next operation step by the conveyor belts 121 and122.

The series of operations set forth hereinabove are repeatedly performedto subject the base plates to sputtering treatment continuously withoutany interruption.

In the aforesaid construction, when enough cooling of the base plates 3is not unobtainable merely by radiation cooling, cooling means relyingon heat transfer, such as by bringing a water cooling rod into directcontact with each base plate, may be additionally used.

In the embodiment shown and described, the sputtering chamber isconstituted by the sputter-etching chamber 54, sputtering chamber 55 andcooling chamber 56. Depending on the use to which the apparatus is put,either one or both of the sputter-etching chamber 54 and cooling chamber56 may be dispensed with. More specifically, when a certain type ofsemiconductor element is produced, it is not necessary to remove a filmof an oxide, such as SiO₂, from the surface of the wafers bysputter-etching. In this case, the sputter-etching chamber 54 may bedispensed with. However, it has been ascertained that baking should beperformed for each base plate so that the base plate is advantageouslybe subjected to baking one by one by heating same with a heater withoutsubjecting same to sputter-etching in the sputter-etching chamber 54.

In the embodiment shown and described, there is provided conveyor meanscomprising a pair of conveyor belts for conveying the base platesubstantially in a horizontal position, there is provided a base platestoring means comprising a cassette elevator and a base plate cassette,and there is provided an opening means in the form of a gate valveadapted to open only when the base plate travels between the chambers.It is to be understood, however, that the invention is not limited tothe specific forms of the conveyor means, base plate storing means andopening means, and that any other suitable form may be used as desired.

According to the invention, a sputter-etching electrode, a heater, asputtering electrode, a shutter and a cooling means constitutesputtering means, and an exhaust port and a vacuum pump constituteevacuating means.

The apparatus according to the invention has the aforesaid constructionand operates as described hereinabove. According to the invention, allthe chambers are separate from and independent of one another to ensurethat each treatment assigned to each chamber is positively performed. Byvirtue of this feature, a film of high quality can be formed on eachbase plate in a stable manner with high productivity on a continuousmass-production basis.

According to the invention, the conveyor means is operative to support abase plate in a substantially horizontal position. This enables transferof the base plate from one chamber to the next with a higher reliabilitythan would be the case if the base plate were conveyed in a vertical ortilting position.

FIG. 6 shows in a schematic view the embodiment of the apparatus inconformity with the invention described hereinabove. As shown, the firstintermediate chamber 53 and the second intermediate chamber 57 areinterposed between the inlet chamber 52 and the sputtering chamber 55and between the sputtering chamber 55 and the withdrawing chamber 58respectively. The two chambers 53 and 57 are evacuated through theexhaust ports 76 and 112 respectively to a predetermined pressure level.

A plurality of untreated base plates 3 are placed in the inlet chamber52 in atmospheric condition which is evacuated by the exhaust pump 76 toa predetermined pressure level.

At this time, the withdrawing chamber 58 which is vacent after thetreated base plates 3 have been withdrawn therefrom is also evacuated bythe exhaust pump 112 to a predetermined pressure level.

After the inlet chamber 52 is evacuated to the predetermined pressurelevel, the gate valve 71 mounted between the inlet chamber 52 and firstintermediate chamber 53 is opened and the base placed 3 placed in theinlet chamber 52 are all transferred to the first intermediate chamber53. After the transfer of the base plates 3 is finished, the gate valve71 is closed and the inlet chamber 52 is restored to an atmosphericpressure level to allow untreated base plates to be placed therein forthe next performance.

While the inlet chamber 52 is being evacuated again by the exhaust pump79, the plurality of base plates 3 stored in the first intermediatechamber 53 are successively fed one by one to the sputtering chamber 55by conveyor means, not shown, to form a film of the desired thicknessthereon before being stored in the second intermediate chamber 57. Whenall the base plates stored in the first intermediate chamber 53 are allsubjected to sputtering treatment and then stored in the secondintermediate chamber 57, the gate valves 77 and 106 mounted on oppositeends of the sputtering chamber are closed. Thereafter the gate valve 113mounted between the second intermediate chamber 57 and withdrawingchamber 58 is opened to transfer to the withdrawing chamber 58 thetreated base plates 3 stored in the second intermediate chamber 57.

At this time, the gate valve 71 is opened to transfer the plurality ofbase plates 3 stored in the inlet chamber 52 of a predetermined pressurelevel to the first intermediate chamber 53. 200 designates a powersource for supplying a sputtering voltage to the sputtering electrode90.

By continuously repeating the aforesaid operations, the followingeffects can be achieved.

(1) The arrangement whereby the base plates 3 fed from the firstintermediate chamber 53 to the sputtering chamber 55 can be subjected tosputtering treatment while the inlet chamber 52 and withdrawing chamber58 are being evacuated eliminates wasting of time, thereby increasingproductivity.

(2) The inlet chamber 52 and withdrawing chamber 58 that are repeatedlyhave their pressures changed from atmospheric to vacuum are indirectlyin communication with each other through the intermediate chambers 53and 57, and the gate valves 71 and 77 and 106 and 113 do not open at thesame time. This is conductive to prevention of contamination of theatmosphere of the sputtering chamber with the components of theatmosphere, thereby improving the quality of the film formed on eachbase plate.

Another embodiment of the sputtering apparatus in conformity with theinvention will now be described by referring to FIGS. 7 and 8. A reservevacuum chamber 152, a pretreating chamber 153 and a sputtering chamber154 are defined in a sealed casing 151. The pretreating chamber 153 andsputtering chamber 154 will generally be referred to as a sputtertreatment chamber 155.

Gate valves 156 and 157 are mounted between the reserve vacuum chamber152 and pretreating chamber 153 and between the pretreating chamber 153and sputtering chamber 154 respectively. The gate valves 156 and 157 areeach provided with an air cylinder, not shown, so that they are openedwhen the base material 3 to be treated, such as a wafer, is transferredbetween the respective chambers.

The reserve vacuum chamber 152 has connected thereto a vacuum pump 159via a main valve 158, a rough drawing line 160, an atmosphere leak line161 and a lid 163 opened and closed for moving a cassette 162 into andout of the chamber 152, and two sets of cassette elevators 164 and 165and a base plate conveyor belt 166 are mounted in the chamber 152. Themain valve 158 is opened and closed by an air cylinder, not shown. Thecassette elevators 164 and 165 are moved up and down by the combinationof motors 167 and 168, screws 169 and 170 and nuts 171 and 172. Thecassettes 162 and 173 are formed such that they are placed on thecassette elevators 164 and 165 respectively and include shelves arrangedto support the base plates 3 thereon. The base plate conveyor belt 166is driven by a motor 174 for conveying the base plates between the twocassettes 162 and 173 and between the reserve vacuum chamber 152 andpretreating chamber 153.

The pretreating chamber 153 is connected to a vacuum pump 176 via a mainvalve 175, and has an argon gas line 177 connected thereto. Asputter-etching electrode 178, a base plate conveyor arm 179, two setsof base plate conveyor belts 180 and 181 and a heater 182 is mounted inthe chamber 153. The base plate conveyor arm 179 has two fingers 183 and184 and is capable of vertical movement and rotary movement by means ofan air cylinder and a motor, not shown. The two sets of base plateconveyor belts 180 and 181 are driven by motors 185 and 186respectively, and as shown in FIG. 3, the base plate conveyor belts 180and 181 are pivotable as a whole by means of another motor, not shown.The heater 182 is in a position C as shown in FIG. 7.

The pressure in the pretreating chamber 153 is kept at a level, such as10⁻³ Torr, which is suitable for performing sputter-etching duringoperation at all times by adjusting the flow rate of the argon gasintroduced through the argon gas line 177 and the speed at which thechamber 153 is evacuated by the vacuum pump 176.

The sputtering chamber 154 is connected to a vacuum pump 188 via a mainvalve 187, and has an argon gas line 189 connected thereto. A sputteringelectrode 190, base plate conveyor belts 87 and 88, a rise mechanism 89,a shutter 92 and an adhesion shield 91 are mounted in the chamber 154.The base plate conveyor belts 87 and 88 are driven by a motor 195 forconveying the base plate between the gate valve 157 and rise mechanism89 which is driven by a motor 196 for bringing the base plate 3 into anupright position in which it is juxtaposed against the sputteringelectrode 90, after the base plate 3 is delivered by the base plateconveyor belts 87 and 88. The sputter 92 is driven by a motor, notshown, and the adhesion shield 91 performs the function of reducing theamount of the sputtering material that might adhere to the innersurfaces of the chamber 154 after its atomic particles are released.

The pressure in the sputtering chamber 154 is kept at a level which issuitable for performing sputtering treatment during operation at alltimes by adjusting the flow rate of the argon gas introduced through theargon gas line 189 and the speed at which the chamber 154 is evacuatedby the vacuum pump 188, so that it is possible to minimize theinfluences exerted by the sputtering chamber 154 by impure gases thatmight be produced. The arrangement whereby the means for bringing thebase plate to a substantially upright position in which it is juxtaposedagainst the sputter treatment means in the sputtering chamber 154enables the amount of foreign matter that might be deposited on the baseplate to be minimized.

In operation, the lid 163 of the reserve vacuum chamber 152 is removedand the cassette 162 stroting the base plates 3 to be treated is placedon the cassette elevator 164. After the lid 165 is placed in positionagain, rough evacuation of the chamber 152 is effected by means of arough evacuating pump, not shown, through the rough evacuating line 160.Then the main valve 158 is opened to evacuate the reserve vacuum chamber152 by means of the vacuum pump 159 to create a vacuum of about 10⁻⁵Torr, for example. Thereafter the cassette elevator 164 is moveddownwardly by the motor 167, screw 169 and nut 171 cooperating with oneanother until the lowermost base plate 3 in the cassette 164 is broughtinto contact with the base plate conveyor belt 166, which is driven bythe motor 167 to convey the base plate 3 to the position of the cassette173 to place it on one of the shelves in the cassette 173. The cassetteelevator 165 is moved upwardly by the motor 168, screw 170 and nut 172cooperating with one another a distance corresponding to the pitch ofthe shelves, to be ready for receiving the next following base plate 3.By repeating the process described hereinabove, all the base plates 3 inthe cassette 162 are transferred to the cassette 173. Then the gatevalve 156 is opened and the cassette elevator 165 is moved downwardly adistance corresponding to the pitch of the shelves, to deliver the baseplate 3 to the pretreating chamber 153 by the base plate conveyor belt166. Thus the delivery of the base plates 3 to be treated to thepretreating chamber 153 and receiving of the treated base plates 3 fromthe pretreating chamber 153 can be effected by using the single reservevacuum chamber 152, thereby enabling the construction of the apparatusto be greatly simplified.

As shown in FIGS. 7 and 8, when the base plate 3 is delivered from thereserve vacuum chamber 152 to the pretreating chamber 153, the baseplate conveyor arm 179 is disposed in an upper position, the finger 183is in a position A, the finger 184 is in a position B, and the baseplate conveyor belts 180 and 181 are in horizontal position.

The base plate 3 delivered through the gate valve 156 is conveyed by thebase plate conveyor belt 180 driven by the motor 185 to the finger 183in position A. After the gate valve 156 is closed, a motor, not shown,is actuated to cause the base plate conveyor belts 180 and 181 to movein pivotal movement about points P and Q respectively, to place the baseplate 3 on the finger 183. Then the base plate conveyor arm 179 descendsafter rotating until the finger 183 comes to a position B, to place thebase plate 3 on the sputter-etching electrode 178. A sputter-etchingvoltage is impressed on the sputter-etching electrode 178 to subject thebase plate 3 to sputter-etching treatment for removing an oxide filmthat is formed on the base plate 3. This permits an electric current tobe passed in good condition between the base plate 3 and a thin filmformed thereon by sputtering (an aluminum coat deposited by vaporizationin vacuum). Then the base plate arm 179 is moved upwardly and rotateduntil the finger 183 reaches position C, and the heater 182 is actuatedto heat the base plate 3. Then the base plate conveyor arm 179 isrotated until the finger 183 reaches position D, and the base plateconveyor belts 180 and 181 are pivotally moved by motors, not shown,until they assume a horizontal position. The result of this is that thebase plate 3 on the finger 183 is placed on the base plate conveyor belt181. After the gate valve 157 is opened, the motor 186 is actuated todeliver the base plate 3 to the sputtering chamber 154. After the baseplate 3 is delivered to the sputtering chamber 154, the gate valve 157is closed and the next following base plate 3 is received from thereserve vacuum chamber 152, to repeat the aforesaid process ofsputter-etching treatment and heating treatment described hereinabove.Then the base plate 3 on the finger 183 stands by in position B, thefinger 184 stands by in position D and the base plate conveyor belts 180and 181 stand by in their horizontal position.

In the sputtering chamber 154, the base plate delivered through the gatevalve 157 is conveyed, by the base plate conveyor belts 87 and 88 drivenby the motor 195, to the rise mechanism 89 in a horizontal position.Then the rise mechanism is driven by the motor 196 to pivotally moveuntil the base plate 3 is brought to a substantially upright position,and the shutter 92 is opened by a motor, not shown, to allow a thin filmto be coated on the base plate 3 by sputtering treatment effected by thesputtering electrode 90 having a sputtering voltage impressed thereon.The sputtering material may be aluminum. After the base plate 3 issubjected to sputtering treatment for a predetermined period of time,the rise mechanism 89 is restored to its horizontal position and thebase plate 3 is delivered to the finger 184 of the pretreating chamber155 by means of the base plate conveyor belts 87 and 88 passing throughthe gate valve 157. The base plate conveyor belts 180 and 181 arepivotally moved to an upright position and the base plate conveyor arm179 is rotated to place the base plate 3 to be treated on the finger 183in position D and to place the base plate 3 that has been treated inposition C. Thereafter the base plate 3 to be treated is delivered tothe sputtering chamber 154 in the same manner as described hereinaboveto subject same to sputtering treatment, while the base plate 3 inposition C that has been treated is brought to position A by rotatingthe base plate conveyor arm 179, before being delivered to the reservevacuum chamber 152 by reversing the process followed before as describedabove. In the reverse vacuum chamber 152, the base plate 3 that has beensubjected to sputtering treatment passes through the cassette 173 beforebeing stored in the cassette 162, and the next following base plate 3 isdelivered from the cassette 173 to the pretreating chamber 153.

The aforesaid series of operations are repeated to subject all the baseplates stored in the cassette 173 of the reserve vacuum chamber 152 tosputtering treatment and stored the treated base plate in the cassette162. Then leak gas is introduced into the reserve vacuum chamber 152through the leak line 161 to render the pressure therein atmospheric,and thereafter the lid 163 is removed to withdraw the cassette 162 fromthe chamber 152, thereby completing a series of sputtering operations.

To subject the base plate both to baking treatment and sputter-etchingtreatment before it is subjected to sputtering treatment requires theprovision of the pretreating chamber 163. More specifically, it isimpossible to form a thin film by sputtering on the base plates if thebase plates 3 are stored in bulk in the reverse vacuum chamber 142 to besubjected to baking therein. It is necessary to subject one base plateafter another to baking treatment by using a heater in the pretreatingchamber that is provided specially in this embodiment.

When the reserve vacuum chamber 152 is disposed adjacent the pretreatingchamber 143, impure gases in the reverse vacuum chamber 152 might beintroduced into the sputtering chamber 154 through the pretreatingchamber 153 each time the gate valve 157 is opened. When this is thecase, the film formed on the base plate might have its quality reducedand it would be impossible to indert or withdraw the cassette and baseplates into and out of the reserve vacuum chamber 152 unless all thebase plates that have been subjected to sputtering treatment are storedin the reserve vacuum chamber 152, so that the apparatus would have alow throughput. This problem can be obviated by providing between thereserve vacuum chamber 152 and the pretreating chamber 153 anintermediate chamber in which a cassette having a large number of baseplates stored therein can be placed.

In the embodiment shown and described hereinabove, no conveyor jigs areused and the base plates are conveyed by themselves. Thus the amount ofimpure gases introduced into the sputtering chamber can be greatlyreduced by not using conveyor jigs. At the same time, deterioration inthe quality of the film formed on each base plate due to the impuregases can be avoided, and heating and cooling can be performed in ashort period of time because the thermal capacity of wafers is low.

In the embodiment shown and described hereinabove, there is providedrise means in the sputtering treatment chamber which is operative tobring each base plate to an upright position in which it is juxtaposedagainst the sputter treating means. This is conductive to prevention ofthe deposition of foreign matter on the base plate which might otherwiseoccur due to sudden bursting of the sputtering electrode or fall offlakes. Moreover, it is possible to keep the base plate and thesputtering electrode stationary in juxtaposed relation while asputtering operation is being performed, thereby increasing the speed atwhich films are formed on the base plates.

FIG. 9 is a schematic view of the embodiment shown and describedhereinabove. In this case, the reserve vacuum chamber 152 serves both asthe inlet chamber 52 and the withdrawing chamber 58 shown in FIG. 6.Means is provided in the chamber 152 for introducing the base platesthereinto and withdrawing same therefrom when the atmospheric pressureprevails therein and for evacuating the chamber 152 to a predeterminedpressure level by the vacuum pump 159. An intermediate chamber 201 isevacuated by a vacuum pump 202 at all times to create a vacuum thereinand provided with means for successively delivering base plates 3 to betreated to the sputtering chamber 154, and means for receiving andstoring the treated base plates 3 from the sputtering chamber 154. Likethe embodiment shown in FIG. 6, the embodiment shown in FIG. 9 enablesthe base plates 3 stored in the intermediate chamber 201 to besuccessively delivered to the sputtering chamber 154 while the reservevacuum chamber storing therein a large number of base plates 3 to betreated in the next following operation is being evacuated by the vacuumpump 202, at the same time as the operation of storing again the baseplates 3 that have been subjected to sputtering is performed. This isconductive to increased productivity. In this case, it is necessary thatthe intermediate chamber 201 deliver the treated base plates to thereserve vacuum chamber 152 after receiving the base plates to be treatedfrom the reserve vacuum chamber 152. Thus to meet this requirement, thereserve vacuum chamber 152 is designed to have a capacity large enoughto treat twice the predetermined number of base plates to be treated.

From the foregoing description, it will be appreciated that the presentinvention can have application not only in sputtering apparatus but alsoin other similar apparatus, such as an apparatus for continuousdeposition of metal in vacuum, that requires similar treatment to begiven in vacuum.

The invention can achieve the effects of saving the wasted time andincreasing the productivity of the operation in vacuum as compared withapparatus of the prior art while improving the quality of the filmformed on the object by avoiding contamination of the atmosphere in thesputtering chamber.

What is claimed is:
 1. An apparatus for performing continuous treatmentin vacuum, comprising:(a) an inlet chamber having atmospheric leak meansconnected thereto and including therein a cassette elevator for movingupwardly and downwardly a cassette in which a number of shelves arearranged in a vertically spaced relation to receive a number of articleswith predetermined spacing intervals defined thereamong, said inletchamber being adapted to subject, collectively, the number of articlesreceived in said cassette to evacuation treatment; (b) a firstintermediate chamber including therein a cassette elevator for movingupwardly and downwardly a cassette in which a number of shelves arearranged in a vertically shaped relation to receive the articles withpredetermined spacing intervals defined thereamong, said firstintermediate chamber being adapted to receive therein the number ofarticles in a manner that the articles are received in the cassettelocated therein; (c) a vacuum treating chamber having at least onevacuum treating means mounted therein; (d) a second intermediate chamberincluding therein a cassette elevator for moving upwardly and downwardlya cassette in which a number of shelves are arranged in a verticallyspaced relation to receive the articles with predetermined spacingintervals defined thereamong, said second intermediate chamber beingadapted to receive therein the number of articles in a manner that thearticles are received in the cassette located therein; (e) a withdrawingchamber including therein a cassette elevator for moving upwardly anddownwardly a cassette in which a number of shelves are arranged in avertically spaced relation to receive said articles with predeterminedspacing intervals defined thereamong, said withdrawing chamber beingconnected to atmospheric leak means; (f) opening means provided betweenthe adjacent chambers, said opening means being normally closed andopened only when said articles are passed therethrough one by one; (g)conveyor means mounted in each of said chambers for horizontallyconveying each of said articles as a single body through said openingmeans; and (h) evacuating means connected to each of said chambers; (i)said inlet chamber, first intermediate chamber, vacuum treating chamber,second intermediate chamber and withdrawing chamber being arrangedsuccessively in a direction in which the articles are successivelytransferred; (j) the apparatus being constructed such that, while thenumber of articles in said inlet chamber and said withdrawing chamberare being subject, collectively, to the evacuation treatment, thearticles received in the cassette in said first intermediate chamber aretaken out successively one by one and horizontally conveyed by saidconveyor means and the respective articles thus successively conveyedare successively subject to the vacuum treatment by said vacuum treatingmeans and then conveyed by said conveyor means successively into thecassette in said second intermediate chamber.
 2. An apparatus as claimedin claim 1, wherein said vacuum treating chamber includes a treatingchamber having heating means mounted therein for effecting bakingtreatment of said articles, and a sputtering chamber containing thereinsputter treating means for effecting sputter treatment of the articleswhich have been subject to baking treatment in said treating chamber. 3.An apparatus as claimed in claim 2, wherein said treating chamberincludes therein means for effecting sputter-etching treatment of saidarticles.
 4. An apparatus for performing continuous treatment in vacuum,comprising:(a) an inlet and withdrawing chamber having atmospheric leakmeans connected thereto and including therein a plurality of cassetteelevators for moving upwardly and downwardly each of a plurality ofcassettes each having a number of shelves arranged therein in avertically spaced relation to receive a number of articles withpredetermined spacing intervals defined thereamong, said chamber beingadapted to subject, collectively, the number of articles received insaid cassettes to evacuation treatment; (b) an intermediate chamberincluding therein a plurality of cassette elevators for moving upwardlyand downwardly each of a plurality of cassettes each having a number ofshelves arranged therein in a vertically spaced relation to receive thenumber of the articles with predetermined spacing intervals definedthereamong, said intermediate chamber cassettes including a firstcassette for receiving the number of the articles not yet subjected tovacuum treatment and a second cassette for receiving the articles havingbeen subjected to the vacuum treatment; (c) a vacuum treating chamberhaving at least one vacuum treating means mounted therein; (d) openingmeans provided between the adjacent chambers, said opening means beingnormally closed and opened only when said articles are to be passedtherethrough successively one by one; (e) conveyor means mounted in eachof said chambers for horizontally conveying each of said articles as asingle body through said opening means; and (f) evacuating meansconnected to each of said chambers; (g) said respective chambers beingarranged such that the articles may be transferred successively from theinlet and withdrawing chamber, through the intermediate chamber, to thevacuum treating chamber, and then from the latter vacuum treatingchamber, through the intermediate chamber, to the inlet and withdrawingchamber; (h) the apparatus being constructed such that, while the numberof articles in said inlet and withdrawing chamber are being subject,collectively, to the evacuation treatment, the articles received in saidfirst cassette in said intermediate chamber are taken out successivelyone by one and conveyed horizontally by said conveyor means and therespective articles thus successively conveyed are successively subjectto the vacuum treatment by said vacuum treating means in said vacuumtreating chamber and then conveyed by said conveyor means successivelyinto said second cassette in said intermediate chamber.
 5. An apparatusas claimed in claim 4, wherein said vacuum treating chamber includes atreating chamber having heating means mounted therein for effectingbaking treatment of said articles, and a sputtering chamber containingtherein sputter treating means for effecting sputter treatment of thearticles which have been subjected to baking treatment in said treatingchamber.
 6. An apparatus as claimed in claim 5, wherein said treatingchamber includes therein means for effecting sputter-etching treatmentof said articles.
 7. An apparatus as claimed in any one of claims 4 to6, further comprising outside storing means provided adjacent the inletside and outlet side, respectively, of said inlet and withdrawingchamber, each of said storing means including a cassette elevator formoving upwardly and downwardly the cassette receiving therein the numberof the articles.
 8. An apparatus as claimed in one of claims 2, 3, 5 or6, wherein said sputtering chamber includes therein means for bringingeach of said articles to a substantially upright position in which itfaces said sputter treating means, so as to enable to effect sidesputtering.
 9. An apparatus for performing continuous treatment invacuum, comprising:(a) an inlet chamber, an intermediate chamber, and atleast one vacuum treating chamber having at least one vacuum treatingmeans therein, arranged in the indicated order in a direction in whichbase plates are successively transferred; (b) opening means in a wall atthe inlet of said inlet chamber, and between adjacent chambers, saidopening means being normally closed, and being opened only when eachbase plate is transferred therethrough; (c) base plate storing meanslocated in each of said inlet and intermediate chambers for receivingand storing a plurality of base plates; (d) a first conveyor meanslocated exclusively within the confines of said inlet chamber, firstconveyor means being constructed and arranged for successively,directing receiving each base plate from the base plate storing means insaid inlet chamber and, without leaving said confines, transferring onlyeach base plate so received through the opening means in the wallbetween the inlet means and the successively adjacent chamber; (e)second conveyor means located exclusively within the confines of saidintermediate chamber, said second conveyor means being constructed andarranged for directly receiving and conveying each base plate,transferred into said intermediate chamber, into the intermediatechamber base plate storing means and for directly receiving andconveying each base plate from the intermediate chamber base platestoring means and conveying only each base plate into the successivelynext chamber, without leaving said intermediate chamber confines; and(f) third conveying means located exclusively within the confines of thevacuum treating chamber for receiving each base plate transferredtherein and for conveying each base plate out of the vacuum treatingchamber after treating thereof.
 10. An apparatus according to claim 9,further comprising a second intermediate chamber and a withdrawingchamber successively, located downstream of said vacuum treatingchamber, in a direction of travel of said base plates; base platestoring means located in each of said second intermediate chamber andsaid withdrawing chamber; fourth and fifth conveying means locatedexclusively within the confines of said second intermediate andwithdrawing chambers, respectively, for directly receiving and conveyingeach base plate, received into the respective chamber, into therespective base plate storing means, and for receiving each base platefrom the respective storing means and conveying same out of therespective chamber without leaving the confines thereof.
 11. Anapparatus according to claim 9, wherein the inlet chamber also serves asan outlet chamber, said inlet chamber and intermediate chamber havingseparate base plate storing means for separately storing incominguntreated and outgoing treated base plates.
 12. An apparatus accordingto one of claims 9, 10 or 11, wherein said base plate storing meanscomprises magazines having receiving shelves which are displaceable intoand out of cooperative alignment with a respective one of the conveyormeans.